About 1,500 union workers from Unite Here Local 5 returned to work at the Hilton Hawaiian Village Resort and Spa in Waikiki after they walked off the job Thursday to protest job security, benefits and wages.

The Wisconsin-based International Foundation of Employee Benefit Plans, which counts the International Brotherhood of Teamsters among its largest clients, has threatened to cancel its Nov. 14-17 conference in Honolulu if labor issues aren't resolved.

The conference has been booked since 1986 and was expected to bring more than 10,000 visitors to Hawaii and generate about $40 million in economic activity, the Honolulu Star-Advertiser reported Tuesday.

Hawaii's entire visitor industry will suffer if the conference pulls out, said David Lewin, general manager of the Hyatt Regency, which is holding 3,500 to 4,000 room nights for the International Foundation.

"It would be very unfortunate for the state, for the city and for all the workers because that business will not be replaced," Lewin said. "Hawaii, Waikiki specifically, would normally rely on Japan for those days, but because that convention is on the books, we've pushed away all the Japanese business and it will not be booked in the short term."

The foundation isn't likely to come to Hawaii unless the hotel worker labor union offers assurances that it's making progress with hoteliers during negotiations, Lewin said.

The International Foundation couldn't be reached for comment Monday.

Hilton, which has 9,200 room nights reserved for the conference, expects to resume discussions with the foundation Tuesday, said Jerry Gibson, Hilton Hawaiian Village's area vice president and managing director.

"If you extrapolate the taxes and how many people the conference would put to work, it means a whole lot to the state," Gibson said. "We hope in the end everything works out well."

Hilton and Local 5 are scheduled to return to the bargaining table Oct. 25 and 26, Gibson said. Hilton has offered raises as well as full pension and health benefits for employees' families.

Workers like Kaleo Aarona, a Hilton Hawaiian Village reservationist, said Hilton hasn't offered a fair contract.

"So far they've only offered us a nickel raise and they are trying to outsource everything from reservations to food and beverage," Aarona said.

The strike was coordinated with related strikes in Chicago and San Francisco by workers with similar bargaining goals.